1. Field of the Invention
The invention disclosed herein relates to the security of sensitive data stored, processed and distributed using electronic circuits. More particularly, the invention relates to the identification of individuals prior to accessing/using data, and the execution of security controls upon unauthorized attempts to access/use said data.
In recent years there has been an explosion of electronic devices that individuals may use for storing and transmitting sensitive data. In a low-security example, portable devices like a Palm™ or BlackBerry handheld computer typically contain software for e-mail, along with options for storing credit cards, schedules, and other data. Most people wish to protect this information, but most handheld devices rely on their operating system to secure data. Unfortunately, the most common operating systems for these handheld computers were not designed with security as the main goal, and retrofitting basic security mechanisms has been clumsy.
A growing number of electronic devices, such as smart cards, are intended to specifically identify and authenticate users using the public key infrastructure, which requires secure storage of private keys. These devices are common in building security; for example, an individual with proper authorization to access a facility is assigned a smart card and an asymmetric key pair. A certificate authority generates a digital certificate for the public key, which is stored in the smart card. The private key is also stored on the smart card. When the individual places his smart card in the reader at the access point of the facility, the card transmits its digital certificate, and the reader challenges the card to encrypt a supplied string with the individual's private key. The reader obtains the public key out of the digital certificate and decrypts the private key-encrypted string to verify that the keys are related. This has an inherent problem because there is no guarantee that the individual using the private key is the assigned owner of the smart card. Furthermore, it is fairly simple for an experienced attacker to gain access to keys stored on the card.
Some handheld devices, such as Hewlett Packard's iPAQ PocketPC h5450, include biometric sensors for improved personal identification before allowing access to sensitive data. An individual possessing this device is instructed to enroll one or more of his fingerprints into the device's software. The enrolled fingerprint can be used as the sole password or as an alternative to a typed password. This type of device can be a substantial improvement on traditional data-access methods, because the biometric can be definitively tied to a single individual. However, if the sensitive data is stored or transmitted insecurely, the biometric authentication does not substantially hinder an attacker from probing the memory and compromising it.
These concerns have contributed to the marketing of products billed as ‘secure memory’ or ‘secure processor’. These products are typically constructed with varying degrees of security; one lower degree is considered ‘tamper-evident’, in which an unskilled observer would see that someone had attempted to maliciously gain access to secured data. A higher level is ‘tamper-resistant’, in which the product actively resists tampering by use of a self-destruct mechanism, an impermeable substance that coats the components storing sensitive data such as a polymer-based coating or other so-called “conformal coating”, or some other process. Furthermore, these products may encrypt input/output lines, mislabel parts, and perform other types of obfuscation.
2. Description of the Related Art
U.S. Pat. No. 5,533,123 to Force, et al., discloses programmable distributed personal security inventions. The patent teaches a “Secured Processing Unit” (‘SPU’) comprising an “SPU chip” and a microprocessor designed especially for secure data processing. The invention integrates keys, encryption and decryption engines, and algorithms in the SPU of the invention. Purportedly, the security process is portable and easily distributed across physical boundaries. The invention is based upon three interdependent subsystems. The first subsystem of the invention is a detector subsystem, which alerts an SPU to the existence and to the character of a security attack. A second subsystem is a filter subsystem that correlates data from multiple detectors, then assesses the severity of the attack against the risk to the SPU's integrity, both to its secret data and to the design of the SPU itself. A third subsystem is a response subsystem for generating responses, or countermeasures, calculated by the filters to be most appropriate under the circumstances, in order to deal with the attack(s) detected. Force does not disclose identity credential verification within the SPU.
U.S. Pat. No. 5,825,878 to Takahashi discloses a secure embedded memory management unit for a microprocessor. A microprocessor memory management apparatus is used for encrypted instruction and data transfer from an external memory. Physical security is obtained by embedding the direct memory access controller on the same chip with a microprocessor core, an internal memory, and encryption/decryption logic. Data transfer to and from an external memory takes place between the external memory and the memory controller of the memory management unit. All firmware to and from the external memory is handled on a page-by-page basis. Since all of the processing takes place on buses internal to the chip, detection of clear unencrypted instructions and data is prevented. Takahashi does not disclose any capability, anticipation, intention, or provision for including identity credential verification on the management unit or within the microprocessor core.
U.S. Pat. No. 5,832,207 to Little, et al., teaches a secure module including a microprocessor and a co-processor. The electronic module is provided with at least one microprocessor and a co-processor deployed into a single integrated circuit. The electronic module can be contained in a small form factor housing. The electronic module provides secure bi-directional data communication via a data bus. The electronic module may include an integrated circuit including a microprocessor and a co-processor adapted to handle 1,024-bit modulo mathematics primarily aimed at RSA calculations. The electronic module is preferably contained in a small token-sized metallic container. The module preferably communicates via a single wire data bus using a one-wire protocol. Little et al. does not disclose personal identification systems.
U.S. Pat. No. 5,894,550 to Thireit discloses a method of implementing a secure program in a microprocessor card, and a microprocessor card including a secure program. The invention claims that a program can be made secure relative to a CPU. The invention accomplishes this by storing in a first memory zone predetermined address functions that are directly executable by the CPU. The first memory zone is then write-protected, then the program is stored in a second memory zone in the form of a series of instructions that are executable within the second memory zone or that activate functions contained in the first memory zone.
U.S. Pat. Nos. 5,481,265, 5,729,220, 6,201,484 and 6,441,770 to Russell detail a handheld device used to authenticate persons and said device to remote computer systems. The invention further includes a “kill switch” or “kill signal” enabling the computer system to remotely disable the handheld device and restrict further emissions. However, the system is primarily targeted at local area network applications and does not anticipate or suggestion broader applications.